                                      (utils/get-stack-trace (Exception.)))
                           (let [new-state
                                 (swap! parent-state inc)]
-                            ;; Should get 3 message packets:
+                            ;; I'd like to get 3 message packets here:
                             ;; 1. ACK
                             ;; 2. message being echoed
                             ;; 3. EOF
+                            ;; What I'm getting instead is:
+                            ;; 1. ACK
+                            ;; 2. message being echoed
+                            ;; 3. message being echoed because I havent responded with an ACK
+                            ;; There may be ways around this, but none of the ones that come
+                            ;; to mind just now seem worth the time/effort.
+                            ;; This test pretty obviously isn't about a
+                            ;; realistic message exchange. It's really
+                            ;; just about verifying that I got the echo.
+                            ;; Everything else going on in here is really just
+                            ;; a distraction from that fundamental point.
+                            ;; They're good distractions, and the system's gotten
+                            ;; much more robust because of them.
+                            ;; FIXME: Revisit this soon.
                             (when (= 3 new-state)
                               (log/info prelog
                                         "Echo sent. Pretending other child triggers done")

            io-handle (message/start! initialized  parent-cb child-cb)]
        (dfrd/on-realized child-finished
                          (fn [success]
                            (is (= success ::specs/normal)))
                          (fn [failure]
                            (is (not failure) "Child echoer failed")))

                      ;; There's nothing on the other side to send back
                      ;; an ACK. But it should have been sent.
                      (is (= msg-len (from-child/buffer-size outgoing)))
                      ;; The EOF still doesn't look like it's getting sent.
                      ;; Although it must be for the parent to have signaled
                      ;; that it's done.
                      ;; TODO: Figure out what's going on.
                      (is (= 0 (count (::specs/un-sent-blocks outgoing))))
                      ;; This includes both the packet we're echoing back
                      ;; and the EOF signal.
